Most major Gulf markets struggled in the final trading session of the week on Thursday, as a rally fuelled by optimism around COVID-19 vaccine developments lost steam.

Financial markets globally have gained in most sessions over the past couple of weeks as U.S. drugmakers Pfizer Inc and Moderna Inc, and British firm AstraZeneca  released positive data on the effectiveness of their vaccine candidates.

Investors are optimistic that progress made on the vaccine front would help economies worldwide recover at a faster pace than expected.

Saudi Arabia's benchmark index fell about 0.6% after a four-session winning run but was on track to eke out a fourth straight weekly gain.

Financial stocks dragged down the index with the top three losers belonging to that sector.

Al-Rajhi Bank and National Commercial Bank declined 0.4% and 1%, respectively.

Dubai's main share index retreated 0.4%, with top lender Emirates NBD and real estate stock Emaar Properties declining 0.9% and 1.5%, respectively.

The Dubai benchmark has gained for the past four sessions in a row.

The Abu Dhabi index eased 0.4%, with First Abu Dhabi Bank and telecom major Emirates Telecom shedding 0.5% and 0.4%, respectively.

In Qatar, the index edged down 0.1%, with Industries Qatar shedding 1.4%.

(Reporting by Aby Jose Koilparambil in Bengaluru; Editing by Subhranshu Sahu) ((abyjose.koilparambil@thomsonreuters.com; +91 (0)8061822683;))